Hermetically sealed compressor suction tube assembly

ABSTRACT

A hermetic compressor unit comprising a hermetic casing containing a compressor including a cylindrical block having an arcuate surface engaging the inner surface of the casing and a suction tube assembly for connecting the compressor to a refrigeration system. The suction tube assembly comprises a steel tubular connector including an end portion extending into an opening in the casing and a sleeve member having a higher ductility than steel that includes a reduced end extending into a suction passage in the block and an enlarged portion engaging the suction tube connector. A steel tubular fitting including an end portion extending into the reduced portion of the sleeve member and a shoulder portion extending into the enlarged portion of the sleeve member that simultaneously compresses the sleeve member in the suction passage and connector to effectively seal the compressor casing and suction tube assembly to the compressor.

United States Patent [191 [111 3,871,800 Slayton Mar. 18, 1975HERMETICALLY SEALED COMPRESSOR [57] ABSTRACT SUCTION TUBE ASSEMBLY [75]Inventor: Curtis R. Slayton, Fern Creek, Ky. [73] Assignee: GeneralElectric Company,

{22] Filed: Mar. 11, 1974 [2]] Appl. No.: 449,720

[52] US. Cl. 418/248 [51] Int. Cl. F04b 17/00 [58] Field of Search418/248; 417/902; 285/158 [56] References Cited UNITED STATES PATENTS2,447,259 8/1948 Lucke i 285/158 2,764,427 9/1956 Andrus 285/158 X3,209,991 10/1965 Sauber 417/902 X 3,618,990 11/1971 Falke 285/158 X3,767,334 lO/l973 Rinehart 418/248 Primary E.raminerC. J. HusarAssistant Examiner-Leonard Smith higher ductility than steel thatincludes a reduced end extending into a suction passage in the block andan enlarged portion engaging the suction tube connector.

A steel tubular fitting including an end portion extending into thereduced portion of the sleeve member and a shoulder portion extendinginto the enlarged portion of the sleeve member that simultaneouslycompresses the sleeve member in the suction passage and connector toeffectively seal the compressor casing and suction tube assembly to thecompressor.

3 Claims, 3 Drawing Figures HERMETICALLY SEALED COMPRESSOR SUCTION TUBEASSEMBLY BACKGROUND OF THE INVENTION aluminum. When using suchmaterials, the usual brazing and soldering techniques have beenavailable for assuring a fluid tight joint between the copper oraluminum conduit and the steel compressor casing during final connectionof the compressor to the system. Presently available hermeticcompressors such as the one disclosed in US. Pat. No. 3,767,334 by DeanC. Rinehart, assigned to General Electric Co., assignee of the presentinvention, shows a suction tube assembly employing an aluminum conduitjoined to the steel casing and a steel tubular fitting including an endportion press fit into the compressor and a shoulder portion engagingthe aluminum conduit. When the copper or aluminum suction tube assemblyconduits are brazed or soldered to the steel compressor casing, flux isused to protect the joint from oxidation and to remove any oxides whichmay form during the brazing or soldering procedure. While the use offlux insures an acceptable fluid tight joint at the compressor casing italso creates an additional step in the manufacturing of the hermeticcompressor in that the flux and residue caused by the joining proceduremust be completely removed from the casing prior to the final sealing ofthe compressor.

It is therefore an object of the present invention to provide a fluxfree connecting system that mechanically seals the compressor casing andthe suction tube assembly to the compressor.

SUMMARY OF THE INVENTION The present invention is particularly directedto an improved hermetically sealed compressor unit assembly adapted toassure a fluid tight connection between the compressor cylinder and thesuction tube assembly. In accordance with the illustrated embodiment ofthe invention, there is provided a hermetic compressor unit comprising asteel casing and a compressor including a cylinder or compressor blockwhich may be press fit or heat shrunk into contact with the casing sidewall. The block includes a suction passage opening and the casing isprovided with a hole aligned with and larger than the suction passage. Atubular steel connector having an end portion extending into the casinghole to a point adjacent the suction passage opening in the block iswelded to the casing. A tubular sleeve member having a higher ductilitythan steel includes a reduced end portion located in the suctionpassage. A tubular steel fitting having an end portion extends into thesleeve in the suction passage and an enlarged portion extends into thesleeve in the steel connector for simultaneously compressing said sleevemember in the suction passage and connector to seal the casing andsuction tube connector to the compressor cylinder block.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a horizontal sectional view of a refrigerant compressor unitincorporating the present invention;

FIG. 2 is an enlarged section view taken along line 22 of FIG. 1illustrating the construction of the connector portion of the unit; and

FIG. 3 is a view'similar to FIG. 2 illustrating one step in themanufacture of the compressor connector portion.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG 1 of thedrawings, there is illustrated a hermetic rotary compressor unitcomprising a cylindrical casing 10 in which there is disposed a rotarycompressor 12. The compressor includes a cylinder block 14 having aninner cylindrical surface 16 which in combination with an end plate 18and the second end plate (not shown) defines a compressor cylinder 20containing a rotor 22.

The cylinder block 12 includes diametrically opposed legs or extensions24 having arcuate surfaces 26 engaging the inner surface of thecylindrical casing wall 10. In the manufacture of such compressors, thecylinder block may be either pressed into the casing or the casing heatshrunk onto the cylinder block.

A suction passage 28 extends through the cylinder block from one of thearcuate surfaces 26 and into the compressor cylinder 20. The outer endof this passage, as illustrated in FIGS. 2 and 3 of the drawings. is inaxial alignment with a flanged hole 30 in the casing side wall 10. Thehole 30 has a somewhat larger diameter than the passage 28. A compressorof this general construction is shown in US. Pat. No.3,568,7l2-Rinehart. to which reference is made for a more detaileddescription of its construction and operation.

In accordance with the present invention means are provided forconnecting the suction line of a refrigeration system to the suctionpassage 28 To this end in one embodiment of the invention, as shown inFIGS. 2 and 3, there is provided a suction tube assembly 32 whichcomprises a tubular steel connector or conduit 34 secured to thecompressor casing 10, a tubular sleeve member 36 and a tubular steelfitting 38. The steel connector 34 has a reduced end portion 40extending into or through the hole 30 to a point adjacent the arcutesurface 26 of the compressor cylinder block 14. The end portion 40 ispreferably of frustum configuration that permits the end portion 40 ofthe connector 34 to project into the hole 30 and facilitate alignment ofthe connector 34 relative to the hole 30 and passageway 28. The endportion 40 of the connector 34 is welded to the casing 10 at the flangeportion of the hole 30 as indicated at 42 to form a fluid tight sealbetween the casing 10 and the connector 34. In the present embodiment,the opening 37 of the connector 34 adjacent the surface 26 has adiameter smaller than the main tubular body portion of the connector 34but larger than the passageway 28 in the cylinder 14. The tubular sleevemember 36 has been chosen from the group of metals having a higherductility than steel. While in the present embodiment aluminum is usedto fabricate member 36, it should be understood that other ductilematerials relative to steel may be employed. The aluminum member 36 hasa reduced end portion 44 which extends into the cylinder passage 28 andan enlarged portion 46 extending into the connector 34 adjacent theopening 37. The tubular steel fitting 38 is then employed to me- 3chanically connegt the connector 34 to the passage 28. Referring to FIG.3 the tubular fitting 38 is inserted throught'lie connector 34 and intothe aluminum sleeve 36't6 the position shown in FIG. 2. Fitting 38includes a reduced end portion 48 which is press fit into the endportion 44 of sleeve 36in the passage area 28 and a shoulder or enlargedportion 50 press fit into portion 46 of the sleeve 36 that is located inthe opening 37 of the connector 34. ln effect, the tubular steel fitting38 simultaneously compresses the aluminum sleeve member 38 in two areasor critical points; namely, area A in the passageway 28 and area B inthe opening 37 of connector 34. The liquid tight seal provided at pointsA and B are effective to mechanically seal the compressor casing andsuction tube assembly to the compressor 12.

It should be noted that the use of a ductile sleeve member 36 allowsgreater tolerance flexibility. This is expecially true in the passagearea where steel tocast iron seals are possible due to the presence ofgraphite in the cast iron, However, they require extremely closetolerances and as a result create manufacturing difficulties.

Means are also provided in the present embodiment of the invention toprevent galling of the relatively soft sleeve 36 in areas A and B by thesteel fitting 38 that may result in the introduction of foreignparticles into the hermetic compressor. To this end the leading edge offitting 38 is tapered so that the sleeve 36 in area A is compressed by awedging action as fitting 38 if forced into place. The leading edge ofthe enlarged portion 50 is provided with a radius which minimizes thepossibility of galling in area B. In the event galling does occur inarea B, it will be contained in a catch or receiving area 52 that isdefined partially by a circumferentially disposed groove formed in thefitting 38.

For assembly to the suction line 54 of a refrigeration system, the endof the line 54 is slip fit onto the connector 34 and adhesively bondedthereto by use of a suitable adhesive such as an epoxy cement. The useof a steel connector 34 permits the use of a welding-procedure inattaching the connector 34 to the steel casing 10 that is relativelyinexpensive and provides a reliable fluid tight seal. Further, the useofa steel connector 34 provides a compressor that is adaptable for usewith either an aluminum or copper refrigeration system in that theadhesive joint is compatible with both systems.

While there has been shown and described a specific embodiment of theinvention, it will be understood that it is not limited thereto and itis intended by the appended claims to cover all such modifications asfall within the true spirit and scope of the invention.

I claim:

1. A hermetic compressor unit comprising:

a casing including aside wall;

a compressor including a cylinder block positioned in said casing andhaving an outer surface adjacent the inner surface of said casing wall;

a passage in said block opening into said outer surface;

said casing having an opening aligned with and larger than said passage;

a suction tube connector including an end portion ex tending into saidopening in axial alignment with said suction passage, and having anopening larger than said passage;

a tubular sleeve member being of greater ductility than the suction tubeconnector, the sleeve having a reduced end portion extending into saidpassage and an enlarged portion extending into the end portion of saidsuction tube connector; and

a tubular fitting having an end portion extending into said reduced endportion of said sleeve member and a shoulder portion extending into saidenlarged portion of said sleeve member to simultaneously radiallycompress said sleeve member in said passageway and said end portion ofsaid suction tube connector to'seal the casing and suction tubeconnector to the compressor cylinder block.

2. A compresser according to claim 1 wherein said suction tube connectorand said tubular fitting is steel, and said tubular sleeve member isaluminum.

3. A compressor according to claim 1 wherein a circumferentiallydisposed receiving area is provided adjacent said shoulder portion ofsaid fitting to entrap foreign matter that may be caused by thecompression action of said shoulder portion on said sleeve.

1. A hermetic compressor unit comprising: a casing including a sidewall; a compressor including a cylinder block positioned in said casingand having an outer surface adjacent the inner surface of said casingwall; a passage in said block opening into said outer surface; saidcasing having an opening aligned with and larger than said passage; asuction tube connector including an end portion extending into saidopening in axial alignment with said suction passage, and having anopening larger than said passage; a tubular sleeve member being ofgreater ductility than the suction tube connector, the sleeve having areduced end portion extending into said passage and an enlarged portionextending into the end portion of said suction tube connector; and atubular fitting having an end portion extending into said reduced endportion of said sleeve member and a shoulder portion extending into saidenlarged portion of said sleeve member to simultaneously radiallycompress said sleeve member in said passageway and said end portion ofsaid suction tube connector to seal the casing and suction tubeconnector to the comPressor cylinder block.
 2. A compresser according toclaim 1 wherein said suction tube connector and said tubular fitting issteel, and said tubular sleeve member is aluminum.
 3. A compressoraccording to claim 1 wherein a circumferentially disposed receiving areais provided adjacent said shoulder portion of said fitting to entrapforeign matter that may be caused by the compression action of saidshoulder portion on said sleeve.